Method of radio communication



July 23, 1935. H. CHlRElX METHOD OF RADIO COMMUNICATION Filed Dec. 27, 1955 2 Sheets-Sheet 1 LLQl/ I 172 012567 MadZch/r 77 cz'rca'zZ 75 IN VEN TOR HEN/W CH/REl/Y A TTORNE Y July 23, 1935. H CHlREIX 2,009,080

METHOD OF RADIO COMMUNICATION Filed Dec. 27, 1935 2 Sheets-Sheet 2 INVENTOR HE/VR/ v H/RE/X W A%NEY Patented July 23, 1935 PAT v 1 aboaoso, v M -METHODOF RADIO COMMUNICATION, v

' a Henri Chireix, ParisQFrance, assignor" to 0 m;

pagnie Generale De Telegraphic Sans F11, a]

corporation of France Application December 2'7,

1933, Serial No.;704,093 V In Trance December 27, 19 32 6 Claims; c1-.' 25o-'-1 r- The present invention relates to signalling systems employing high frequency currents for the transmission and constitutes in particular an'im provement or modification in'the transmitter of modulated wavesdescribed in the United States patent specifications Nos. 1,882,119 and 1,892,383. The=inventionwill be more readily understood with-reference to the accompanying drawings in which: I Figure 1 shows a-general arrangement of the transmitter according to the invention;

Figure 2 shows a' potential diagram in theoutput :and input circuits of the last amplification stage of the transmitter; Figure 3 indicates a curve showing the angle between input'v'ectors o'fFigl 2 in function of the angle between output vectors of the same figurej Figures 4, 5 and 6 show three species of arg angrlament contained within therectangle V 15 of 1g. i H The Figure 1', analogous to the Fig. zorthe United StatesPatent 1,882,119, shows a trans-' mitter-comprising two difierential circuits 2 and 2'; each one orwmcn is traversed by a current of practically fixed amplitude; but of modulated phase, the two phase modulations being made in opposite senses, Thesephasemodulated currents are obtained'from a carrier wave generator 8. coupled with the'circuits 2, 2" through-the couplings 9, 9". The circuits between the generator 8' and the coupling inductances 9 and 9' are such that the carrier waves fed from 8 to 9" and 9' are in phase opposition The couplingsll and -9' 'deliver'unmodulated components of phase modulat- 35' ed currents togthe amplifiers Mand Id. The generator 8 is coupled, moreover, through the coupling l0 with a modulating arrangement H to deliver thereto carrier waves in phase quadrature with respect to the waves in 9 and 9'. The 40 modulator II is controlled by a microphone l2 or other suitable modulation means and coupled with the circuits 2, 2' through the couplings l3, IS in such a manner that there are delivered two amplitude modulated components which are op- 45 posed to one another and are, moreover, in quadrature to the said unmodulated components flow ing through the circuits 2, 2'. The superimposition of one unmodulated and one modulated como ponent in each? circuit gives the resulting fixed amplitude but phase modulated current, the two phaseimodulations being made in opposite senses. Each of. these currents is amplified in the amplifiers l4,l.|4f'and bothcurrents are combined in a circuit contained within theirectangle [5 to supplying the antenna 5 with a high frequencyvampliy tude modulatedwave.

It has been further shown in-my Patent #1346508, resulting from application ,..Ser. No;

623,333, filed:the 19th July, 1932; that it is neces- 5i saryin orderto obtain the maximum efilciency; from the output of the last amplification stage," to-idetune the oscillatingcircuits of anode the one to higher values andtheother one to lowervalues in such manner as to compensate-for a 10;.

given-condition of .the reactive energy due.1.-to the load reaction; This necessary .det'uning causes: as such 'a disadvantage which the'present inven tion aims to overcome. Under conditions wherethe compensation is a correct one,; the-.excitation 153 of the grid is exactly in phase withthevoltage' developed in the plate circuit, but under all other conditions this is-.-no longer true. with the result that theflamplifier tubes operate lwith an impedance different fronra pure resistance. It 20*- willtherefore be found that ifiduring the cycle of modulation-the phase of' voltage U1 and Uiat the terminals of the output circuits varies byithe' value or (across sectioned zoneinFigure 2) the phase of the excitations V varies by the quantity;

,8, whereby ,6 is greater than a. v Furthermore Figure 3shows the course'of the curve indicating the relation between the angle of the, phase dilference betweenxthe vectors U in the plate circuit and-the angle of the phase difierence between the vectors V in'the grid circuit; This curve intersects the 45 lineat the angle eifecting' theicompensation. This disadvantage therefore involves a lack of linearity in the modulation in that the antenna current does not-vary quickly enough inthe regionlwhere' the compensationof the reactive power is carried out.

According to the presentjinvention 'thisfldefi ciency can be remedied in'that the inverse defectv for the grid circuit is produced in the. opposite 40 sensathat is to sayin eliecting the condition in whichthe angle through which the excitation of the grid of the final stage passes be greater-than the, angle through which the electromotive force of the excitation of this circuit; or the excitation of thepreceding amplification =stage passes. With a sweeping a sumcient soas to obtain the sweeping zone pot the grid excitations the aforee mentioned deficiencywill be completely compensated. A 1 .1" I .7 The solution for accomplishing this result'and which forms the object of the present invention consists. of applying-the invention of U. S. Patent #l,946,308 both-to i the grid circuit and itothe plate circuit of the amplifier end stage (enter a 6 NT, F CE:

circuit preceding the end stage), and under conditions in which the load of the grid circuit is at maximum when the useful load in the output end circuit is at minimum and vice versa. It will also be seen that whatever circuit may be adapted for obtaining modulation by the difference in phase, the ult i be ras es in 5 19 1, a wa h t he reactive powencausing the load in the grid cir-, cuits an'din the plate circuits of the same tube, is of inverse sign (efiect of self inductance by the, one, effect of the capacitance by the other one). Consequently in order to obtain a, true tuningof the grid and plate circuits for a given condition it is required to detune the grid and plate circuits of the same tube or of the same amplifier branch in different senses.

An embodiment of the invention is shown in Figure 4 by way of example which represents an arrangement contained in the rectangle l5, .of

Fig. 1, in which I and I designate two grid circuits=receiving from: couplings 2, 2- the excitations different in phase and preferably in opposite.

phase at smallloads while the point opposite the grids of: these circuits is connected="-to the, usual negative pole. These oscillatory circuits excite tubes 3 3 whichsupply; respectively the oscillatory circuits 4; 4; 5. represents diagrammatically the eload" resistance, for instance atuned antenna;

andt'are the lead capacities and coil inductances as ordinarily used.

The 'oscillatingoutput circuits 4 and 4' are chosen in .accordancewith Patent #l,946,308 so that-liistunedbelow the carrier wave and l, for instance, above the latter. According to the improvements obtainable by the present invention, the circuits I and l' arealso detuned but in opposite. senses. that is to say when 4 is detuned below the carrier wave in thecase of the example shown, I is detuned above it .and when 4' is detuned above the carrier wave, I" must be detuned below it. Finally these circuits l and I operate upon a common load'represented by the resistances T.

It will also be. realized that the small loadsin 5 on the contrary correspond with the great loads.

in I and vice versa.

It will: be seen, in effect, that the load resistance 5 is'affected'by the geometrical sum of the vectors U, whilst theresistance I is traversed by acurrent due to the geometrical difference of the vectors V- 'Theseconditions have been indicated by means of conventional signs and as indicated in the figure.--

There are numerous variations of the same characteristic possible as for instance those shown in Figures 5 and 6' in which equivalent elements are designated by the same reference numerals as in Figure 4;

InFig. 5, the-resistance 'l is loaded by the geometrical sum of vectors 'V, whilst the resistance 5 is charged by the geometrical difierence'of vectors U. "In Fig. 6, the resistance 5 is as in Fig.4 charged by the geometrical sum of vectors U, but'the circuits l'and l'are so interconnected that the resistance 1 is afiected by the geometrical sum of vectors (+V) and (-V). In all the cases of the figures it will be readily seen that with the small-loads of the plate-circuits correspond the heavy loads of the grid circuits.

The detuniiig-of the grid and plate circuits of the-same tubeon the other hand are carried out at opposite senses. For all cases the excitations of smallloads is marked'by the conventional signs-i and comprising ajsource of electrical energy of carrier; frequency, two difierential circuits coupled with said source'and' containing each an ampliflcationchain, oscil ating circuits disposed in the output and in the input of the last amplifier stage in each chain, the two output oscillating circuits being detuned respectively the one above, the other belcw the said carrierpfrequency whilst the corresponding; input oscillating. circuits areinversely tuned, the one below, the other-above the carrier frequency; means coupled with the;

said source for diverting a portion of energy and for transforming its phase in quadratic relation ship tothe original phase, means for amplitude modulating the lastsaid energy, portion, means for superimposing the modulated energy on the;

unmodulated energy in; each of the differential circuits so that the resulting wave. in eachcircuit is phase modulated and is of practically fixed amplitude and so that the phase modulations vary in opposed senses in the'respective circuits, and a commonoutput circuit coupled to said output oscillating circuits for combining the phase modulated waves to produce an amplitude mod u-..

lated' wave. I

2. An amplitude modulated wave transmitter comprising a source of electrical energy of carrier.-

frequency, two differential circuits coupled with said source and containing each an amplification chain, oscillating circuitsdisposed in the output.

and in the input of the last amplifier stage in each chain, the two output oscillating circuitsbeing detuned respectively the one above, the other below the said carrier frequency, whil t the corresponding. input oscillatingcircuits are in: versely, detuned, the one below, theother above the carrier frequency, means for modulating the phase of the energy in the said differential cir-.- cuits so that the resulting wave in each circuit is. phase modulated and is of'practically fixed amplitude and so that the phase modulations vary in opposed senses in the respective circuits, and a common output circuit coupled to said output oscillating circuits for combining the phase modulated waves to produce an amplitude modue lated wave. 1

7 3. A transmitter as'recited in claim 2 in come bination with means for rendering the common output circuit load maximum when the load of the input oscillating circuits is minimum and vice versa. 1

4. A transmitter as recited in claim 2 comprising at least one resistance interconnecting the input oscillating circuits of the last amplifier stages of the two differential circuits;

5. A transmitter as recited in claim 2 comprising at least one resistance interconnecting the input oscillating circuits of the last amplifier stages of the two differential circuits; means for applying to the said resistance the'difierence of the potentials in the said input circuits, and means for applying to the output common circuits the sum of the potentials in the output oscillating circuits of each of the differential circuits.

6. A transmitter as recited in claim 2 comprising at least one resistance interconnecting the 5 input oscillating circuits of the last amplifier stages of the two differential circuits, means for applying to the said resistance the sum of the potentials in the said input circuits, and means for applying to the output common circuit the difference of the potentials in the output oscillating circuits of each of the difierential circuits.

HENRI CHIREIX. 

